1. Field of the Invention
Embodiments of the disclosure relate in general to the field of integrated circuits and, more particularly, to improved electrical connectors for integrated circuit packages comprising ball grid arrays or land grid arrays.
2. Description of the Related Art
A ball grid array (BGA) or land grid array (LGA) package offers a number of advantages relative to other, older package types, e.g., quad flat pack (QFP) and pin grid array (PGA), including small size, high input/output (I/O) pin count, improved electrical performance, low profiles, and good yields. These packages can be constructed with a substrate that can be either single or multi-layer. Substrates are fabricated with plastic or ceramic material, electrically conductive traces, and with planes being formed on a surface of each layer of the substrate. The surface of the substrate opposite from the semiconductor die or integrated circuit (IC) contains a plurality of solder balls that are soldered to the pads on a printed circuit board (PCB), thus attaching the package to the board. The semiconductor die is electrically connected to the substrate by either flip-chip (solder bump) interconnect or wire bonding. In both instances, the die is also generally encapsulated by plastic to protect it from the external environment.
One of the benefits of BGA packaging is the increase of achievable I/O densities compared to older package options. Since BGA packaging places contacts over the entire surface of the chip instead of just around the edges, IC designers can place more I/Os in a given package size while using relatively looser tolerance compared to older peripheral lead types. This offers additional benefits to board designers who are not subsequently constrained to use the fine pitches that are typically necessary for older high-lead count packages.
BGA packaging brings new challenges to the packaging designers, particularly in high-speed IC applications, where the effects of electromagnetic interference (EMI) become extremely important, and BGA I/O densities exacerbate this problem. Signal integrity is another important issue for packages and boards emerging from high-speed transceivers in high-end FPGAs and ICs. Impedance control is critical for package-to-board transitions connecting signals from layer to layer.
In view of the foregoing, it would be desirable to provide a high-speed BGA semiconductor device having improved electromagnetic interference (EMI) and signal integrity characteristics. In particular, it would be desirable to provide a hexagonal ball-grid array having improved electrical performance.